How Many Mystery Snails per Gallon?

If you are a new snail owner you may be thinking how many mystery snails should keep per gallon of aquarium water.

However, mystery snails can multiply very quickly. For one mystery snail you need two and half gallons of tank water. 

There is a general rule that 1 inch of snails including shells need 1 gallon of water, where mystery snails can grow from 2.5 to 3 inch. Another way is, as you can keep 1 or 2 mystery snails in five gallon of water.

If your tank is larger than 5 gallons, divide your tank capacity by gallon number 5 then multiply the result by 2 you will get the maximum number of mystery snails that you should keep in your aquarium. 

For example for 20 gallons of tank capacity {(20 gallon tank ÷ 5=4)×2} = 8. 

However, in this article I will deeply discuss how many mystery snails per gallon and how to control your snail overpopulation. So read till the end.

How Many Mystery Snails per Gallon

How Many Mystery Snails Per Gallon?

Mystery snail is the first choice of the aquarists for its attractive appearance and non aggressive behavior.

They are very useful for their algae eating habits. That’s why you need to maintain the correct number of mystery snails to get benefit. 

But if you do not maintain its population it will create problems. To maintain the population you need to know the perfect number of snails per gallon. 

According to the expert, for 5 gallons of tank water you should keep only 2 mystery snails. And if your tank capacity is large you can follow the above mentioned  way to know how many mystery snails per gallon.

However, here is a list to understand the number of mystery snails per gallon. 

  • For 1 or 2 gallons of water you should not keep any mystery snails
  • For 2.5 gallons of water you can keep only 1 mystery snail
  • For 5 gallons of water you should keep 1 or 2 mystery snails
  • For 10 gallons of water you should keep 2 or 4 mystery snails
  • For 15 gallons of water you should keep 6 mystery snails
  • For 20 gallons of water you can keep 4 to 8 mystery snails
  • For 30 gallons of water you can keep 6 to 12 mystery snails
  • For 36 gallons of water you can keep 14 mystery snails
  • For 40 gallons of water you can keep 8 to16 mystery snails
  • For 55 gallons of water you can keep 22 mystery snails
  • For 60 gallons of water you can keep 24 mystery snails
  • For 75 gallons of water you can keep 30 mystery snails

By the way you do not need to follow ‘5 gallon of water for 2 mystery snails’ rule. Because some other factors like plants, filter etc can not hold in this small tank size.

You can only get a basic knowledge about how many mystery snails you can put in your aquarium according to your tank size. It will be better if you keep mystery snails under the number mentioned above. 

Can you Have Too Many Mystery Snails in a Fish Tank?

Yes you can keep too many mystery snails in a fish tank. But to avoid a huge population of snails it will create problems in your fish tank.

It will make the environment threatening and mystery snails will be stressed because of overcrowded tank situations. 

Also as the tank situation will go bad day by day if the mystery snails live in this condition they will damage the plant life. 

Though mystery snail love algae but in a small tank a huge number of mystery snails will not be satisfied with it. After finishing the algae they will move to your tank plant. 

For instance, you always need to take a large fish tank to keep too many mystery snails. Otherwise in a small fish tank you should not keep too many and need to control overpopulation.

How Should You Set Up a Mystery Snail Tank?

When you decide to set up a tank for your mystery snails you need to consider some factors before purchasing a tank.

Primary Surpose

First select why you want to keep mystery snails in your tank. If its only for algae control technique you can keep only 1 or 2 mystery snails which is enough for you.

Also if your tank has no algae producing problem you can skip them. Or if you want to keep them for their unique pattern also you can keep one or two mystery snails. It will not hamper your fish egg at all.

Tank Size

Before putting in mystery snails you have to take at least 2.5 gallon of tank. Because it was already mentioned above that for 1 mystery snail you need 2.5 gallons of water. So think about your tank size first.


If you are a beginner do not invest your money on a little tank. Because it is hard to maintain the water parameter in a little aquarium.

So expand your budget and purchase at least a mid-size aquarium. You can get a mid-size 20 gallon tank for under 150 dollar.

Maintenance and Care

You need to maintain regular care of your mystery snails. Because they need a stable water parameter and calcium rich diet.

Though mystery snails are an algae eater, you should feed your mystery snails regularly.


Mystery snail is a peaceful snail. They do not attack any of their tankmates. So avoid selecting any aggressive tankmate.

You can keep mystery snails in your fish tank because fish does not disturb the mystery snail.

How to Control the Snail Population in Your Aquarium?

If you see the overgrowth of mystery snails in your fish tank you should take steps to control their population. You can keep only male mystery snails or keep assassin snails to the aquarium.

However, here are some methods to stop the mystery snail overpopulation in your fish tank.

Keep male mystery snails

The most effective way to control mystery snails population is to only keep male mystery snails. To reproduce the mystery snails need both female and male gender.

Because without male mystery snails female snails will lay infertile eggs which will not hatch any healthy snail baby.

Therefore, it is a good prevention method to stop the growth of mystery snails.

Manually remove mystery snails

If you do not follow any preventative way and see the rapid growth of mystery snails, start to remove the snails with your hand.

Remove the snails until you get a proper number of mystery snails. Also you can give the unnecessary snails to any tank owner. Or you can sell them in any store.

Add Predators

You can take advantage of predators. Keep assassin snails or some fish which eat mystery snails.

You Can add goldfish, betta fish, clownfish, yoyo, dwarf puffers, etc. They will eat enough mystery snails and decrease the number of overgrowth snails.

Final Words

To keep mystery snails in your tank you can follow the rule 2 snails per 5 gallon of water. Otherwise follow the above mentioned structure to know how many mystery snails per gallon of water.

Also keep a proper number of mystery snails in your tank or you will face many problems which will be created by overpopulated snails.